Yesterday I was thinking that one drawback to doing GTD in GMail is that the emails stick together in a "conversation", and you could have several tasks going on in that conversation, and some could be @action whereas others could be @waitingfor. If only there were a way to mark certain emails in that conversation as special and needing review.

And then I realized: that's what the blue Stars are for! Marking emails as special!

GMail is just so useful and anticipatory.